NEW YORK (Bloomberg) ? Weatherford International Ltd., the fifth-largest US oilfield contractor, will replace Toys "R" Us Inc. in the Standard & Poor's 500 index on a date yet to be announced.

Toys "R" Us, the second-largest US toy seller, is being acquired by a group of investors. The retailer is based in Wayne, New Jersey. Oil and natural-based producer Denbury Resources Inc. will replace Houston-based Weatherford in the Standard & Poor's MidCap 400, S&P said in a statement today on its Web site.

NCI Building Systems Inc., a maker of metal products for the nonresidential building industry, will replace OshKosh B'Gosh Inc., a children's clothing retailer, in the S&P SmallCap 600 after the close of trading on July 14. OshKosh is being acquired by Carter's Inc., which makes baby clothes.

The shares of Weatherford, which is registered in Bermuda, but operates out of Houston, rose as high as $60.69 in after- hours trading. Earlier it rose 92 cents to $59.51 in New York Stock Exchange composite trading.